Analysis of Heterosis for Yield and Its Attributing Traits in Bread Wheat (Triticum aestivum L. em. Thell)

Abstract

Developing effective breeding strategies remains critical for achieving sustainable improvements in the genetic yield potential of wheat. The present investigation was carried out at the Research Farm, Department of Genetics and Plant Breeding, School of Agriculture, Lovely Professional University, Punjab, during the Rabi season of 2023–2025. Thirteen genetically diverse wheat genotypes, including ten lines from NBPGR and three testers from IIWBR, were crossed in a Line x Tester mating design to generate 30 F1 hybrids. These hybrids, along with the parents and a standard check variety, were evaluated to estimate heterosis, governing yield and its related traits. The experimental material was sown in a randomized block design (RBD) with three replications. Observations were recorded on eleven quantitative characters viz., days to 50% flowering, days to maturity, plant height (cm), number of effective tillers per plant, length of main spike (cm), number of spikelets per main spike, number of grains per main spike, thousand grain weight (g), biological yield per plant, harvest index and grain yield per plant (g). Data were collected from all 30 F1 hybrids, 13 parents and one standard check for each of the traits under study. The analysis of variance revealed highly significant differences among the genotypes, indicating sufficient genetic variability for all the traits studied. Positive and significant heterosis over the standard check was observed in several crosses, with IC534770 x PBW–677 showing the highest positive heterosis for grain yield per plant. A considerable range of both positive and negative heterosis was observed for grain yield per plant among the F1 hybrids. In terms of better parent heterosis, five crosses- IC-532908 x SKW 196, IC-60213 x SKW 196, IC-532155 x PBW 677, IC-532780 x PBW 677 and IC-534770 x SKW 196-exhibited significant positive heterosis. Similarly, six crosses-IC-532908 x SKW 196, IC-60213 x SKW 196, IC-532155 x PBW 677, IC-532780 x PBW 677, IC-532802 x SKW 196 and IC-534770 x SKW 196-recorded significant positive heterosis over the standard check. However, the number of crosses showing significant heterosis and the extent of heterosis varied across traits. Overall, the study revealed that several hybrids demonstrated substantial and desirable heterosis for a range of agronomic traits. The presence of wide-ranging heterosis, both in positive and negative directions, along with significant and favorable heterotic responses from certain crosses, indicates the strong potential of these hybrids for further genetic improvement in bread wheat.